Image processor and image processing method

ABSTRACT

An image processor having an image compression unit to generate first compressed image data by dividing input image data into blocks of M×M pixels with regard to at least luminance signals (Y) of the input image data, wavelet-converting the image data in units of blocks, and reducing the number of bits by quantization, a memory to store the first compressed image data, a coordinate calculator to calculate coordinates to deform images by coordinate conversion and output coordinate information, a compressed image deforming unit to generate compressed deformed image data by reading out the first compressed image data stored in the memory while conducting coordinate conversion based on the coordinate information from the coordinate calculator, and a first image decompression unit to decompress the compressed deformed image data to obtain decompressed image data.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is based on and claims priority pursuant to 35U.S.C. §119 to Japanese Patent Application No. 2011-060553, filed onMar. 18, 2011, the entire disclosure of which is hereby incorporated byreference herein.

BACKGROUND OF THE INVENTION

The present invention relates to an image processor and an imageprocessing method that correct image deformation using coordinateconversion. Description of the Related Art

In recent years, camera systems have been developed in which imagestaken by the fisheye lens of a rearview camera to enable the driver tosee what is behind the vehicle are processed to correct distortionstemming from the fisheye lens or subjected to image deformation basedon viewpoint switching to obtain an overhead image, thereby providingvehicle drivers with images easy to view (for example, Japanese PatentApplication Publication Nos. JP-2009-177703-A and JP-2010-81479-A).

In this type of camera system, part of an image is cut out and the partof the image output by the camera is enlarged to achieve the capabilitydescribed above by correction. Therefore, to express details of theenlarged image, use of high-definition cameras having one megapixels ormore have come to be demanded in recent years.

However, high-definition cameras have problems with the access speed andcapacity of the memory used as the frame buffer.

With regard to the access speed, random access to the frame buffermemory address is required for coordinate conversion. In addition, thethroughput of DRAMs, etc. for use in the frame buffer is large for aburst read in which sequential addresses are read but decreasesdrastically in the case of random access. Therefore, read speed is tooslow for high-definition images, thereby making it impossible tocontinue coordinate conversion. Furthermore, to conduct coordinateconversion for high-definition images, interpolating between pixels isrequired. In interpolation, for output of a single pixel, reading datafor two (for interpolation only in the horizontal direction) or four(for both horizontal and vertical interpolation) pixels around thatsingle pixel is required, and with a significantly high throughput.

Furthermore, with regard to the capacity of the memory, to store thedata obtained by a high-definition camera, a memory having a relativelylarge capacity is required in comparison with a low-definition camera.For example, just for storing each piece of RGB 8-bit data using acamera having around one megapixels, the capacity required is somewherearound the following:

-   -   VGA (0.3 M pixels): 640×480×24 (RGB)×two faces (double        buffer)=14.7 Mbits.    -   WVGA (0.1 M pixels): 1,280×800×24 (RGB)×two faces (double        buffer)=49.2 Mbits.

In an effort to solve this problem, for example, JP-2008-61172-Adescribes a technique of processing the data to be stored in the framebuffer. However, the capacity required is still around two-thirds thatcalculated, which is not a sufficient reduction for a camera having acapacity on the order of megapixels. As a result, use of expensive RAMshaving a large capacity is required.

SUMMARY OF THE INVENTION

In view of the foregoing, the present invention provides an imageprocessor having an image compression unit to generate first compressedimage data by dividing input image data into blocks of M×M pixels withregard to at least luminance signals (Y) of the input image data,wavelet-converting the image data in units of blocks, and reducing thenumber of bits by quantization, a memory to store the first compressedimage data, a coordinate calculator to calculate coordinates to deformimages by coordinate conversion and output coordinate information, acompressed image deforming unit to generate compressed deformed imagedata by reading out the first compressed image data stored in the memorywhile conducting coordinate conversion based on the coordinateinformation from the coordinate calculator, and a first imagedecompression unit to decompress the compressed deformed image data toobtain decompressed image data.

As another aspect of the present invention, an image processing methodincluding the steps of compressing input image data to generate firstcompressed image data in which the input image data are divided intoblocks of M×M pixels with regard to at least luminous signals (Y),followed by wavelet conversion by block and reduction of the number ofbits by quantization, storing the first compressed image data in amemory, calculating coordinates to obtain and output coordinateinformation to deform the input image by coordinate conversion,generating compressed deformed image data by reading out the firstcompressed image data stores in the memory while conducting coordinateconversion based on the coordinate information, and decompressing thecompressed deformed image data to obtain decompressed image data.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Various other objects, features and attendant advantages of the presentinvention will be more fully appreciated as the same becomes betterunderstood from the detailed description when considered in connectionwith the accompanying drawings, in which like reference charactersdesignate like corresponding parts throughout and wherein:

FIG. 1 is a diagram illustrating the entire configuration of oneembodiment of an image processor according to the present disclosure;

FIGS. 2A and 2B are diagrams of describing the principle of generationof deformed images by coordinate conversion;

FIG. 3 is a diagram illustrating a processing of image compression andimage decompression according to the present application;

FIGS. 4A and 4B are diagrams illustrating block division and memorystoring of a screen;

FIG. 5 is a diagram illustrating the processing of interpolation;

FIGS. 6A and 6B are diagrams illustrating an example of an originalimage and an output image;

FIG. 7 is a diagram illustrating the relationship between the boundaryof a block and the interpolation processing;

FIG. 8 is a diagram illustrating the screen before the block unit isshifted one pixel;

FIG. 9 is a diagram illustrating the screen after the block unit isshifted one pixel;

FIG. 10 is a diagram illustrating an example of a memory space for twoimages;

FIG. 11 is a diagram illustrating an example of a memory space employinga double buffer system;

FIG. 12 is a diagram illustrating the entire configuration of anotherembodiment of an image processor according to the present disclosure;

FIGS. 13A and 13B are diagrams of describing an decompression processingat a second image decompression unit of FIG. 12; and

FIG. 14 is a diagram illustrating the frequency characteristics of theluminance signals of an image display.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present disclosure are described in detail withreference to accompanying drawings.

Embodiment 1

FIG. 1 is a diagram illustrating the entire of one embodiment of theimage processor of the present disclosure.

A sensor unit 100 has an image processor in addition to an optical lenssystem, a camera such as a charge-coupled device (CCD) and acomplementary metal-oxide semiconductor (CMOS), an A/D conversioncircuit. The sensor unit 100 converts the optical image of an objectinto electric signals followed by A/D conversion and processing such asBayer Interpolation, YUV conversion, and sharpness and outputs imagedata sequentially. An image processor 200 inputs the image data (YUVdata) sequentially from the sensor unit 100 followed by distortioncorrection processing or viewpoint switching processing by coordinateconversion to output deformed images sequentially. The structure andprocessing of the image processor 200 are described later.

A display unit is connected to the image processor 200 and the outputimage data therefrom are displayed as they are or after the data areconverted into video signals of NTSC format.

In this embodiment, the image processor 200 has an image compressionunit 210 to generate compressed image data by compressing the inputimage data (YUV data), a frame buffer 220 to store the compressed imagedata, an image decompression unit 230 to conduct an decompressionprocessing of the compressed image data (compressed deformed image data)read out from the frame buffer 220, an interpolator 240 to conduct aninterpolation processing of the decompressed image data, a coordinatecalculator 250 to calculate the coordinate to deform the image bycoordinate conversion, and a compressed image deforming unit 260 togenerate compressed deformed image data by reading out the compressedimage data from the frame buffer 220 based on the output information(coordinate information) from the coordinate calculator 250.

For example, in the case of a vehicle mounted camera system, the imageprocessor 200 is accommodated in a chassis together with the sensor unit100. The chassis is attached to the back of the vehicle for use. Thesensor unit 100 outputs clock signals and horizontal and verticalsynchronizing signals together with image data.

The image processor 200 may generates the clock signals and thehorizontal and vertical synchronizing signals and supplies them toindividual units or the image sensor 100 in the system.

The principle of the generation of deformed images is described first.The deformed image is generated by writing image data (input image)output from the camera as they are once and reading out from differentaddresses (coordinates). FIG. 2 is a diagram illustrating an example inwhich a deformed image is generated by deforming the input image by 90°rotation. FIG. 2A indicates the positional relationship on thecoordinate of two pixels before and after the conversion and FIG. 2Bindicates the positional relationship of the pixels corresponding to theinput image and output image saved in the frame memory. That is, whenthe image data are read out from the frame buffer, the image data of thepixel on the coordinate (x1, y1) on the input image are read out as thepixel on the coordinate (X1, Y1) on the output image. In addition, asthe pixel of the coordinate (X2, Y2) on the output image, the image dataof the pixel on the coordinate (x2, y2) on the input image are read out.This is conducted for each pixel on the input image so that the imagegenerated by deforming the input image by 90° rotation is obtained asthe output image.

As described above, by deforming the image by coordinate conversion, forexample, in a rearview camera to view the back of the vehicle, imagesobtained by a fish eye lens are processed to correct the distortion ofthe image inherent to fish eye images or subjected to image deformationbased on viewpoint switching to obtain an overhead image, therebyproviding vehicle drivers with images easy to view.

As described above, when a camera having a high definition is used, theproblems arise with regard to the access speed and the capacity of thememory for use in the frame buffer. In the present disclosure, thecompressed image data in which image data are compressed are saved inthe frame buffer and used for the process of deforming the image bycoordinate conversion. The entire operation of the image processor 200is described next.

For the input image data (YUV data) from the sensor unit 100, the imagecompression unit 210 divides the luminance signals (Y) into M×M pixelblocks, conducts wavelet conversion in units of block, and thereafterquantizes the data for reducing the number of bits of high frequencycomponents to generate compressed image data (non-invertible compressedimage). In addition, the color signals (UV) are subjected to averagingprocessing by block to generate compressed image data (non-invertiblecompressed image). The image compression unit 210 sequentially storesthe generated compressed image data in the frame buffer 220.

The coordinate calculator 250 calculates coordinates to correctdistortion by coordinate conversion or generate deformed images forviewpoint switching based on the horizontal/vertical synchronizationsignals and outputs the calculation results to a compressed imagedeforming unit 260. To be specific, the coordinate calculator 250calculates the prior-to-conversion coordinates on the input imagecorresponding to the post-conversion coordinate on the output image inorder that the image data of pixels such as coordinates (x1, y1), (x2,y2) on the input image are read out as the pixels of (X1, Y1) (X2, Y2)on the output image (deformed image) when the image data are read outfrom the frame memory as illustrated in FIG. 2.

Normally, the coordinate calculator 250 has multiple coordinateconversion look-up tables (LUT) preliminarily calculated for deformingimages, such as distortion correction, rotation correction, andviewpoint switching correction, and selects a desired coordinateconversion table according to the purpose. The coordinate calculator 250uses the desired coordinate conversion table, reads out theprior-to-conversion coordinates from the table according to thehorizontal/vertical synchronization signal, and outputs it to thecompressed image deforming unit 260.

This obviates the need for calculation of prior-to-conversioncoordinates on the input image corresponding to the post-conversioncoordinate on the output image each time.

The compressed image deforming unit 260 obtains the block containing theprior-to conversion coordinate from the coordinate information receivedfrom the coordinate calculator 250 and reads out the compressed imagedata of the block from the frame buffer 220. In addition, the compressedimage deforming unit 260 outputs information (coordinate information inthe block) indicating the position of the prior-to-conversioncoordinates in the block to the interpolator 240.

For the compressed image data read out from the frame buffer 220, theimage decompression unit 230 conducts reverse wavelet conversion for theluminance signals (Y) to conduct decompression to the image data of M×Mpixels by block. The color signals (UV) are decompressed to image dataof the original format.

For the decompressed image data output from the image decompression unit230, the interpolator 240 calculates and outputs the pixel values of thetarget coordinate in the block by a method such as bilinear based on thecoordinate information in the block received from compressed imagedeforming unit 260 with regard to the luminance signals (Y). The colorsignals (UV), as described later, are output as they are because eachblock has only one piece of information.

Next, the processes are described specifically. The original data areset to have 8 bits for YUV signals per pixel in this example. Withregard to the luminance signals (Y), a single pixel of 8 bits is outputas it is from the sensor unit 100. With regard to the color signals(UV), YUV=4:4:4 are converted into YUV=4:2:2 in the sensor unit 100 andtwo pixels of 8 bits (average of the two pixels) are output for each ofUV signals.

FIG. 3 is a diagram illustrating a specific compression/decompressionprocessing image at the image compression unit 210 and the imagedecompression unit 230.

A single block is 2 pixels×2 pixels here.

For the image data from the sensor unit 100, the image compression unit210 conducts wavelet conversion by block in which a single block is 2pixels×2 pixels to generate LL, HL, LH, and HH components (waveletconversion coefficient) with regard to the luminance signals. Amongthese, the high frequency component of HL, LH, and HH are quantized toreduce the number of bits. To be specific, LL component is 8 bits, HLand LH components are 3 bits, and HH component is 2 bits. Therefore, theluminance signals (Y) are compressed in such a manner that 32 bits arecompressed to 16 bits per block. With regard to the color signals (UV),YUV=4:2:2 are converted into YUV=4:1:1 (average of 2 pixels×2 pixels) byblock. The color signals (UV) after the conversion are 8 bits for each.Therefore, the color signals (UV) are compressed in such a manner that32 bits are compressed to 16 bits per block.

If the Y signals of 4 pixels of a single block are a, b, c, and d, theLL, HL, LH, and HH components are calculated as follows:

LL=(a+b+c+d)/4

HL=(a+c)/2−(b+d)/2

LH=(a+b)/2−(c+d)/2

HH=(a−b)−(c−d)

For the compressed deformed image data read out from the frame buffer220, the image decompression unit 230 conducts a reverse waveletconversion by block to restore data of a single block of 4 pixels withregard to the luminance signals (Y). That is, data of a total of 32 bitshaving a single pixel of 8 bits and a single block of 4 pixels arerestored. The color signals (UV) are converted into the originalYUV=4:2:2. That is, for each UV signal, data of a total of 32 bitshaving 8 bits for two pixels and a single block are restored.

When Y signals having 4 pixels of a single block are a, b, c, and d,these are calculated from the LL, HL, LH, and HH components as follows:

a=(4×LL+2×HL+2×LH+HH)/4

b=(4×LL+2×HL+2×LH−HH)/4

c=(4×LL−2×HL+2×LH−HH)/4

d=(4×LL−2×HL−2×LH+HH)/4

In the case of the embodiment illustrated in FIG. 3, 16 bits of theluminous information and 16 bits of the color information per fourpixels are required while the data amount requiring 24 bits per pixel isrequired in non-compressed state (8 bits stored for each of RGB) for theframe buffer. That is, the frame buffer requires only a third of thenon-compressed state. In addition, burst-writing to perform writing insequential memory addresses at a high speed can be used for the framebuffer. On the other hand, since the amount of 4 pixels includingsurrounding pixels can be read out from the frame buffer by reading dataof a single block of 32 bits with regard to reading-out for output of asingle pixel, interpolating the decimal portion of the coordinateconversion in the XY directions is made possible by using thesesurrounding pixels so that a high quality coordinate conversion ispossible.

A specific image of the block division of the screen and memory storingmethod is illustrated in FIGS. 4A and 4B. In FIG. 4A, a screen of 1,280pixels x 800 pixels is divided into blocks each of which has 2 pixels×2pixels. In the embodiment illustrated in FIG. 3, the compressed imagedata are 16 bits per block for both the luminance signals and the colorsignals. A illustrated in FIG. 4B, the luminance signals and the colorsignals of the single block are stored (burst-writing) in sequentialaddresses in the frame buffer 220. In addition, data of a single blockof 32 bits are read out from the frame buffer 220 by burst-reading of 16bits×2 addresses.

In order to avoid writing and reading of data in the same frame of thememory at the same time, the frame buffer 220 may employ a double buffersystem in which memories for two screens are prepared to separateaddress spaces for writing and reading.

As illustrated in FIG. 5, the interpolator 240 applies the bilinearmethod, etc. for the decompressed data of a, b, c, and d of the 4 pixelsfor a single block with regard to the luminance signals (Y) andcalculates and outputs the weighted average according to the reading-outposition (for example, X=0.2, Y=1.2) of the coordinate information inthe block from the compressed image deforming unit 260. With regard tothe color signals (UV), since the decompressed data from the imagedecompression unit 230 have one piece of color information per block foreach of U and V, the decompressed data are output as they are.

FIG. 6 is a diagram illustrating specific images. FIG. 6A is an originalimage and FIG. 6B is an example of the output image after thecompression, decompression, and interpolation as described above. Theoutput image is almost non-discernable from the original image to humaneyes.

Embodiment 2

In the configuration and operation of Embodiment 1, for example, whenthe luminance information about the position marked by x in FIG. 7 istried to obtain, the position is on the boundary of the blocks so thatthe information of the surrounding four pixels is not obtained from oneblock, thereby making the interpolation impossible.

Therefore, in this embodiment, the image compression unit 210 is dualand the second data compression unit shifts one pixel about theluminance signals followed by block division and generates compressedimage data by block. When the compressed image data are written into theframe buffer 220, the image space in which the block is shifted onepixel are written into the memory in addition to the image space whichis normally processed. The compressed image deforming unit 260 selectsfrom which image space the compressed image data of the block are readout according to the read-out coordinate.

FIGS. 8 and 9 are diagrams illustrating the processing image ofEmbodiment 2. FIG. 8 is a diagram of an image space 1 of the normalprocess (corresponding to Embodiment 1) and FIG. 9 is a diagram of animage space 2 in which one pixel is shifted from the image space 1. Inthe case of the position marked as x in FIG. 7, by using the image space2 of FIG. 9, the luminance signals of the four surrounding pixels aroundthe position marked as x can be obtained from a single block so thatinterpolating is securely conducted.

Although two image compression units and the capacity twice as much arerequired in this embodiment, interpolation is possible in the Xdirection and Y direction when reading out the coordinate of anyposition. When a single block is two pixels×two pixels or more, forexample, four pixels×four pixels, the image space 1 and the image space2 are overlapped a single pixel.

FIG. 10 is a diagram illustrating an example of the arrangement of theimage space 1 and the image space 2 on the memory. Other arrangementsare possible. In the case of the double buffer system, there are fourimage spaces on the memory as illustrated in FIG. 11.

Embodiment 3

FIG. 12 is a diagram illustrating the entire configuration of the imageprocessor of Embodiment 3. This configuration is the same as in FIG. 1except that a second image decompression unit 270 is added downstreamfrom the interpolator 240.

To deform images, image data are read out from the memory (frame memory)by random access. To reduce the cost of the device, inexpensive DRAMsare preferable. However, since inexpensive DRAMs do not have a highdriving frequency so that the random access speed is slow, it is tooslow to calculate necessary address values, for example, to read outdesired pixels in the main scanning direction to output regular NTSC.

In this embodiment, the number of pixels read out in the main scanningdirection output from the frame buffer 220 is set to be smaller than thenumber of pixels of the output screen. For example, the number of pixelsin the main scanning direction from the frame buffer 220 amounts to 500pixels, which is smaller and thereafter, in the second imagedecompression unit 270, the read out pixels are decompressed to 720pixels by the decompression processing in the main scanning direction.

To be specific, in the second image decompression unit 270, the imagedata of 500 pixels per line output from the interpolator 240 are writteninto, for example, an FIFO memory, which is thereafter read out. Whenread enable signals to read out the image data from the FIFO memory areHigh for 14 clocks and Low for 6 clocks, 14 pixels are read out eachtime. This is repeated 35 times and the last time is high for 10 clocksand Low for 10 clocks to read image data of 500 pixels per line.

FIG. 13A is a diagram illustrating an image data set read out from theFIFO memory every time. This image data set is decompressed by theinterpolation processing as illustrated in FIG. 13B. This is repeated35+1 times so that the image data of 500 pixels per line aredecompressed to image data of 720 pixels.

FIGS. 13A and 13B illustrate just an example. The way of decompressionis not limited thereto as long as the number of pixels required tooutput an image finally in the main scanning direction are obtained.

FIG. 14 is a diagram illustrating typical frequency characteristics ofthe luminance signals of a display. When the horizontal definition ofthe NTSC signal is calculated, the result is: 8.0 MHz/30 fps/525 lines=507 lines. As seen in FIG. 14, even when image data of 720 pixels perline are read out from the memory, the output speed to NTSC is abottleneck so that degradation rarely occurs around 500 pixels.

Embodiment 4

In this embodiment, an overlay unit is provided downstream from theinterpolator 240 in FIG. 1 or the second image decompression unit 270 inFIG. 12. In the vehicle mounted camera system, the positions of themarkers such as vehicle width lines or distance lines can be changed tocover many kinds of vehicles. By this overlay unit, such vehicle widthlines or distance lines are overlapped with an output image.

Displaying the vehicle width lines displaying the width of the vehicleor the distance lines displaying the distance from the vehicle on thedisplay of the rearview camera, etc., helps a driver to park a vehiclesafely.

1. An image processor comprising: an image compression unit to generatefirst compressed image data by dividing input image data into blocks ofM×M pixels with regard to at least luminance signals (Y) of the inputimage data, wavelet-converting the image data in units of blocks, andreducing the number of bits by quantization; a memory to store the firstcompressed image data; a coordinate calculator to calculate coordinatesto deform images by coordinate conversion and output coordinateinformation; a compressed image deforming unit to generate compresseddeformed image data by reading out the first compressed image datastored in the memory while conducting coordinate conversion based on thecoordinate information from the coordinate calculator; and a first imagedecompression unit to decompress the compressed deformed image data toobtain decompressed image data.
 2. The image processor according toclaim 1, wherein the image compression unit compresses the input imagedata by converting to YUV=4:1:1 with regard to color signals (UV) of theinput image data.
 3. The image processor according to claim 1, whereinthe image compression unit reduces the number of bits of HL, LH, and HHcomponents among LL, HL, LH, and HH components of the waveletconversion.
 4. The image processor according to claim 3, wherein theimage compression unit reduces the number of bits of HH component most.5. The image processor according to claim 1, further comprising aninterpolator to interpolate the decompressed image data by blockdecompressed by the first image decompression unit with regard to atleast the luminance signals based on the coordinate information in theblock output from the coordinate calculator.
 6. The image processoraccording to claim 5, wherein the interpolator outputs the color signalsas they are.
 7. The image processor according to claim 5, wherein theimage compression unit generates second compressed image data from thefirst compressed image data by shifting the blocks in the firstcompressed image data a predetermined number of pixels with regard to atleast the luminance signals and stores the second compressed image datain the memory, wherein the compressed image deforming unit selects thefirst compressed image data or the second compressed image data so as toconduct interpolation of the pixel situated outermost in the block whenreading the first compressed image data or the second compressed imagedata from the memory.
 8. The image processor according to claim 1,further comprising a second image decompression unit arranged downstreamfrom the first image decompression unit to change a size of an outputimage.
 9. The image processor 200 according to claim 1, wherein thememory 220 employs a double buffer system in which address spaces areseparated for writing and reading-out.
 10. An image processing methodcomprising the steps of: compressing input image data to generate firstcompressed image data in which the input image data are divided intoblocks of M x M pixels with regard to at least luminous signals (Y),followed by wavelet conversion by block and reduction of the number ofbits by quantization; storing the first compressed image data in amemory; calculating coordinates to obtain and output coordinateinformation to deform the input image by coordinate conversion;generating compressed deformed image data by reading out the firstcompressed image data stores in the memory while conducting coordinateconversion based on the coordinate information; and decompressing thecompressed deformed image data to obtain decompressed image data. 11.The image processing method according to claim 10, wherein, in thecompressing step, the input image data are compressed by convertingcolor signals (UV) of the input image data to YUV=4:1:1.
 12. The imageprocessing method according to claim 10, wherein, in the compressingstep, the number of bits of HL, LH, and HH components among LL, HL, LH,and HH components of the wavelet conversion is reduced.
 13. The imageprocessing method according to claim 12, wherein, in the compressingstep, the number of bits of HH component is reduced most.
 14. The imageprocessing method according to claim 10, further comprisinginterpolating the decompressed image data by block with regard to atleast the luminance signals based on the coordinate information in theblock.
 15. The image processing method according to claim 14, wherein,in the interpolating step, the color signals are output as they are. 16.The image processing method according to claim 14, wherein thecompressing step comprises; generating second compressed image data fromthe first compressed image data by shifting the blocks in the firstcompressed image data a predetermined number of pixels with regard to atleast the luminance signals; and storing the second compressed imagedata in the memory, wherein, in the generating compressed deformed imagedata step, the first compressed image data or the second compressedimage data is selected so as to conduct interpolation of the pixelsituated outermost in the block when reading the first compressed imagedata or the second compressed image data from the memory.
 17. The imageprocessing method according to claim 10, further comprising changing asize of an output image.